[Effect of the Pneumococcal Conjugated Vaccines on Burden of all Cause Pneumonia, Bacterial Pneumonia and Empyema in Children].

The aim of this single-center retrospective study was to determine the changes in the burden of allcause pneumonia, bacterial pneumonia and empyema in children aged 0-18 years after the availability of 7-valent pneumococcal conjugated vaccine (PCV7) and 13-valent pneumococcal conjugated vaccine (PCV13) in our country. Children aged 0-18 years who were hospitalized with the diagnosis of pneumonia and treated in Ankara between January 1, 2006 and December 30, 2019 were included in the study. The burden of disease according to the years was calculated as follows: after determining the number of patients with all-cause pneumonia, bacterial pneumonia and the empyema who were admitted to the pediatric infectious diseases service, we divided those numbers to admission numbers to all outpatient clinics in that year as the ratio in 100 000. The years 2006-2007 were accepted as pre-vaccine period, 2009-2010 as PCV7 period and 2012-2019 as PCV13 period. As 2008 and 2011 were the years when PCV7 and PCV13 vaccines implemented into the routine vaccination schedule, they were accepted as transition years and the patient data from these years were not used. All of the patients data were obtained from the patient files. There was a significant decrease in the disease burden of all-cause pneumonia in 0-18 years age and 0-24 months age group after PCV13 period compared to PCV7 period (p<0.001 and p<0.001). A statistically significant decrease was found in all-cause pneumonia among children older than 60 months after PCV13 period compared to PCV7 period and pre-vaccine period (p<0.05 and p<0.01, respectively). When pre-PCV13 (PCV7 and pre-vaccine periods together) and post-PCV13 periods were compared; in 0-18 years age, 0-24 months age and 24-60 months age groups, there was a significant decrease in the burden of disease due to all-cause pneumonia after PCV13 (p<0.001, p<0.001 and p<0.05) period. When the bacterial pneumonia disease burden in PCV13 period was evaluated, bacterial pneumonia disease burden in 0-18 years and 0-24 months age group was found to be significantly lower than in both pre-vaccine and PCV7 periods (p<0.001 and p<0.001). After PCV13 vaccine, the disease burden due to bacterial pneumonia was found to be significantly lower in 0-18 years age, 0-24 months age and older than 60 months age groups compared to pre-PCV13 period (p<0.001, p<0.001 and p<0.01). When PCV7 and PCV13 periods were compared in 0-18 years age group, a significant decrease was found in hospitalizations due to empyema after PCV13 (p<0.05). In conclusion, PCV7 and PCV13 led to a significant reduction in the incidence of all-cause pneumonia and bacterial pneumonia in children.